tmua None Q11

tmua · Uk · specimen_paper1 Exponential Functions Exponential Equation Solving
11. The sum of the roots of the equation $2 ^ { 2 x } - 8 \times 2 ^ { x } + 15 = 0$ is
A 3
B 8
C $\quad 2 \log _ { 10 } 2$
D $\quad \log _ { 10 } \left( \frac { 15 } { 4 } \right)$
E $\quad \frac { \log _ { 10 } 15 } { \log _ { 10 } 2 }$
11. The sum of the roots of the equation $2 ^ { 2 x } - 8 \times 2 ^ { x } + 15 = 0$ is

A 3

B 8

C $\quad 2 \log _ { 10 } 2$

D $\quad \log _ { 10 } \left( \frac { 15 } { 4 } \right)$

E $\quad \frac { \log _ { 10 } 15 } { \log _ { 10 } 2 }$\\